K1 AIOC Hardware Rev 1.2 #93
Conversation
…ted, when a TRS connector is used. If not, then both pads can be used separately
…o supply DC bias using the internal offset calibration feature
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Added an RC-lowpass on the bias net to reduce noise
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…om alternative sources
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Any rough estimates of a timeline for finalizing this variant? I'd definitely be interested in giving it a try, happy to tinker or help with the design a bit if needed! |
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I am planning to do testing and required firmware work around Christmas. |
so i shouldn't buy 1.2 from jlcpcb at this moment? |
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You can, but it will only work after I get those changes in and there is even a slight chance I did a boo-boo. 😁 So in short: you shouldn't, yet |
I've tested most of the current features, working well obviously you're the professional and will improve the firmware and possibly find bugs however for me I've not hit any brick walls yet. 1.3.0 RC2 |
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If you are okay with the audio output being line level and not mic level and the audio input probably being distorted due to the missing DC bias with the old firmware, sure go ahead 😅 |
As you might know I am still in the works for an updated K1 AIOC Hardware. This is still untested!
There have been requests that allow the input/output gain/attenuation be set by software e.g. to control radios that have line level inputs/outputs.
I have started to make changes and named them rev. 1.2. See this schematic
The idea is to use the internal OPAMP to add gain to the 1:2 divider on the input. However the biasing needs to be adjusted to be always at mid-level of the full-scale, so I am planning to use the second OPAMP and the internal calibration feature to do just that.
For the output, I changed to having line-level output if the DAC_ATTEN signal is open drain, and if it is pulled to ground, it should output mic levels.
Let me know if you are interested in this feature and would be able to test the line-level portion, but maybe also the "old" functionality with regular K1 HTs.